Integrated circuits are typically housed within a package that is mounted to a printed circuit board (PCB). The package is designed to protect the integrated circuit device from damage, to provide adequate heat dissipation during operation, and to provide electrical connection between the integrated circuit device and a PCB (e.g., a peripheral card, a motherboard and the like). These conventional packages may include a variety of packages such as pin grid array (PGA), land grid array (LGA), ball grid array (BGA), column grid array (CGA), and other packages. FIG. 1 illustrates a conventional LGA package. Package 100 includes an integrated circuit device 102 that is electrically coupled to the package substrate 104 by a plurality of solder bumps 106. Lands 108, on the bottom surface of the package, are used to electrically couple the package to a corresponding set of lands on a PCB.
As a part of the manufacturing process, integrated circuits typically undergo a variety of functional tests. The present invention is aimed at removing heat from the surface of an integrated circuit that is housed within a package during the functional testing of the integrated circuit device. The functional test is performed before a package is mounted to a printed circuit board. The purpose of the test is to check the functionality and to monitor the electrical performance of the integrated circuit. The environmental test is generally performed within a temperature controlled chamber. A vacuum pickup chuck is typically used to position the package within the chamber. The electrically testing of the integrated circuit is performed by positioning the package within the chamber such that the package contacts are in electrical contact with a corresponding set pogo pins or contact array located on the contactor/load board of the test apparatus. Information pertaining to the electrical performance of the device is gathered during the test. The information is then used to screen out the bad integrated circuits and to classify the integrated circuits according to their operating frequency. This process is commonly referred to as "binning out."
It is commonly known that as the temperature of an integrated circuit rises, the frequency at which the device operates decreases. Therefore, it is important to control the temperature of the integrated circuit during the functional test to ensure that the device is appropriately classified or "binned" according to its operating frequency. It is also important to control the temperature of the integrated circuit since excessive temperatures may affect the performance of the circuit and cause permanent degradation of the device. In addition, it is desirable to hold the temperature of the integrated circuit device at a relatively constant temperature throughout the testing sequence.
The traditional method for cooling integrated devices has been through convection heat transfer. Using this method, heat is dissipated from the integrated circuit through the outer surfaces of the device into still or moving air. As the integration level (i.e., the number of transistors per device) of integrated circuits increases, or the power requirements or the operating speed of integrated circuits increases, the amount of heat generated by these devices increases to a point where conventional convection based solutions are inadequate. Although "active" heat removal methods, such as heat pumps and heat pipe systems, have been developed to cool these high heat dissipating devices within their normal operating environments, there exists a need to provide a method for cooling the integrated circuits during the functional testing of the devices. If the integrated circuit device is not adequately cooled during the test, and is permitted to rise significantly above a designated test temperature, the device may be unnecessarily down-graded into a lower frequency bin. It is also important that the temperature of the integrated circuit device be maintained above the designated test temperature during the functional test sequence in order to ensure that the device is not improperly upgraded into a higher frequency bin.
Thus, what is needed is a method and apparatus for controlling the temperature of an integrated circuit device that solves the problems associated with testing an integrated circuit package.